The present invention relates to a manufacturing method of a head gimbal assembly (HGA) provided with at least one thin-film magnetic head element used in for example a hard disk drive unit (HDD) and to an apparatus for cutting ball bonding connections, used during manufacturing the HGA.
In an HDD, thin-film magnetic head elements for writing magnetic information into and/or reading magnetic information from magnetic disks are in general formed on magnetic head sliders flying in operation above the rotating magnetic disks, respectively.
Each HGA is assembled by mounting the magnetic head slider on a suspension and then by electrically connecting connection pads of lead conductors with terminal electrodes of the magnetic head slider, respectively.
After thus assembling the HGAs, all of the assembled HGAs are finally checked using a dynamic performance (DP) tester to judge whether each thin-film magnetic head element has a desired electrical property or not. Only HGAs judged in this final inspection as products with a good performance are permitted for a shipment or assembling into the HDD.
Recently, an HGA with a wireless suspension using no lead wire but having trace conductors for signal lines has widely spread. In such HGA with the wireless suspension, electrical connection between connection pads of the trace conductors and terminal electrodes of the magnetic head slider are mainly achieved by a wire bonding or a ball bonding.
In the conventional manufacturing process of an HGA with a wireless suspension, particularly of an HGA with a wireless suspension using ball bonding connections, the HGA judged as defective in the final inspection was discarded.
However, a wireless suspension itself is expensive in comparison with a normal suspension, and therefore a ratio of a manufacturing cost of the wireless suspension with respect to a total manufacturing cost of the HGA with the wireless suspension is quite high.
Thus, if all HGAs judged as poor electrical property in the final inspection are discarded, an average manufacturing cost of the HGA will extremely increase.
It is therefore an object of the present invention to provide a manufacturing method of HGA and an apparatus for cutting ball bonding connections, whereby a manufacturing cost of HGA can be decreased.
According to the present invention, a manufacturing method of an HGA includes a step of mounting a magnetic head slider with at least one thin-film magnetic head element on a suspension, this mounting step including electrically connecting the magnetic head slider with the suspension with ball bonding connections, a step of inspecting electrical property of the thin-film magnetic head element, a step of separating the ball bonding connections when it is judged that the thin-film magnetic head element has defective electrical property, a step of detaching the magnetic head slider from the suspension, and a step of mounting a new magnetic head slider with at least one thin-film magnetic head element on the suspension from which the defective magnetic head slider was detached.
When it is detected that the thin-film magnetic head element has defective electrical property, the ball bonding connections between the suspension and the magnetic head slider are separated without discarding the suspension, and then a new magnetic head slider is mounted on the suspension to recondition an HGA. Since the expensive suspension is reused in manufacturing of the HGA, a manufacturing cost of the HGA can be reduced. Also, since the suspensions are reused without discarding all of them in the defective HGAs, this method can contribute to environmental protection.
It is preferred that the ball bonding connections are gold ball bonding (GBB) connections using gold balls. In this case, the separating step may include cutting the gold balls by a cutter blade. Since the material of gold is soft, cutting of the gold balls using the sharp cutter blade is very easy to carry out.
It is also preferred that the cutting of the gold balls includes cutting the gold balls so that a thin gold layer remains on connection pads formed on the suspension. Since whole gold ball is not removed but the thin gold layer is remained on the connection pads, deformation of the suspension due to the cutting of the ball bonding connections can be almost prevented from occurring. Furthermore, since the thin gold layer is remained on the connection pads of the suspension, GBB of electrode terminals of a new magnetic head slider with the connection pads when remounting the slider on the suspension can become easy and a strength of the re-bonded section will increase.
It is preferred that the ball bonding connections are solder ball bonding (SBB) connections using solder balls. In this case, the separating step may include heating and melting the solder balls. It is also preferred that the separating step further includes removing the molten solder ball by vacuum suction.
It is preferred that the detaching step includes heating a part of the magnetic head slider and a part of the suspension to loosen adhesive used to mechanically fix the magnetic head slider to the suspension.
It is also preferred that the method further includes a step of cleaning an adhesion surface of the suspension after the detaching step.
It is further preferred that the method further includes a step of checking performance of the suspension after the detaching step. In this case, the checking step may include checking a load and an attitude angle of the suspension.
It is preferred that the method further includes a step of inspecting electrical property of the thin-film magnetic head element of the new magnetic head slider after the new magnetic head mounting step.
According to the present invention, also, a manufacturing method of an HGA includes a step of mounting a magnetic head slider with at least one thin-film magnetic head element on a suspension, a step of inspecting electrical property of the thin-film magnetic head element, a step of detaching the magnetic head slider from the suspension when it is judged that the thin-film magnetic head element has defective electrical property, a step of cleaning an adhesion surface of the suspension, and a step of mounting a new magnetic head slider with at least one thin-film magnetic head element on the suspension from which the defective magnetic head slider was detached.
Furthermore, according to the present invention, an apparatus for cutting ball bonding connections includes an attachment member for attaching an HGA that includes a suspension with connection pads and a magnetic head slider with at least one thin-film magnetic head element, the magnetic head slider being mounted on the suspension and electrically connected to the connection pads by GBB using gold balls, and a cutter blade capable of moving in parallel with a surface of the connection pads of the suspension attached to the attachment member, the gold balls being mechanically cut and separated by the moving of the cutter blade. Since the material of gold is soft, cutting of the gold balls using a sharp cutter blade is very easy to carry out.
It is preferred that the cutter blade cuts the gold balls so that a thin gold layer remains on the connection pads of the suspension. Since whole gold ball is not removed but the thin gold layer is remained on the connection pads, deformation of the suspension due to the cutting of the ball bonding connections can be almost prevented from occurring. Furthermore, since the thin gold layer is remained on the connection pads of the suspension, GBB of electrode terminals of a new magnetic head slider with the connection pads when remounting the slider on the suspension can become easy and a strength of the re-bonded section will increase.
It is also preferred that the apparatus further includes a blower member for blowing hot air or hot nitrogen gas to the magnetic head slider.
Further objects and advantages of the present invention will be apparent from the following description of the preferred embodiments of the invention as illustrated in the accompanying drawings.